POS0463 REENGINEERING CHIMERIC ANTIGEN RECEPTOR T CELLS FOR TARGETED THERAPY OF LUPUS NEPHRITIS
Authors: C. Solé-Marcé, T. Moline, J. Cortés-Hernández
Journal: Annals of the Rheumatic Diseases (2022)

Background Although the pathogenesis of lupus nephritis (NL) is not completely clear, it is known that the production of anti-dsDNA or anti-C1q antibodies is related to its activity [1]. Despite treatment, approximately 30-40% of patients continue to present a significant number of renal outbreaks [2]. Therefore, there is a growing interest in the development of more specific drugs. As B cells play a central role in the pathogenesis of SLE, the therapy CAR-T cells has been studied reporting good results for the prevention and also for as treatment in murine lupus models [3,4]. Recently, a new selective immunotherapy for autoimmune diseases has been demonstrated by modifying the T cells with a chimeric autoantigen receptor (CAAR) [5]. This novel therapeutic approach could be beneficial in NL with the aim of depleting only anti-DNA producing B cells. In this way, the benefits of anti-CD20 biologics would be obtained, but it would be much more specific, personalized and, surely, effective since only the self-reactive B cells would be destroyed. Objectives To study CAAR-Tcell anti-dsDNA and anti-C1q therapy in NL through in vitro experiments (primary cells and kidney organoids). Methods Synthesis of 6 CAAR anti-dDNA that will be transfected in the primary T cells extracted from patients with NL and healthy controls (N = 10 per group). Through in vitro experiments their ability to lyse the B cells that produce anti-dsDNA or anti-C1q will be evaluated. The two CAAR-Tcell models that is most effective will be evaluated using kidney organoid models obtained from human samples. Results We engineered six human T cells models to express a chimeric autoantibody receptor (CAAR), consisting lupus nephritis autoantigen. As antigens for anti-DNA produced B cells, we designed Heparanase1/2, Histone1 and alpha actinin 1/2 CAAR-Tcells. For anti-C1q produced B cells, we used C1q protein fused to CD19-CD3 signaling domains. The CAAR-Tcells models that exhibited specify cytotoxicity in vitro againts B cells producing anti-dDNA were Heparanase2 and alpha actinin1 CAAR-Tcells (selectivity of 75% vs 45%). C1q CAAR-T cells also presented specificy cytotoxicity for anti-C1q B cells (selectivity of 80%). In vivo imaging assay reveals that C1q or Heparanase2 CAAR-Tcells depleted completly B cells at 48 hours (ratio 1:10, Bcells:CAAR T-cells). We developed 3D in vitro organoid culture using human kidney organoid and B cells from lupus nephritis patients. We evaluated Heparanase2 and C1q CAAR-Tcells using them and we demostrated that C1q CAAR-Tcells could resolved better local kidney inflammation (reduction of IL6, TNF and INF cytokines levels). Conclusion Taken together, these results show that C1q CAAR-Tcells could be an effective and selective immune therapy for treatment of lupus nephritis. Currently, we are evaluated this therapy using NZWB/F1 murine models. References [1]Rekvig OP, Thiyagarajan D, Pedersen HL, Horvei KD, Seredkina N. Future Perspectives on Pathogenesis of Lupus Nephritis: Facts, Problems, and Potential Causal Therapy Modalities. Am J Pathol. 2016;186:2772-2782 [2]Liu Z, Davidson A. Taming lupus-a new understanding of pathogenesis is leading to clinical advances. Nat Med 2012;18:871–82. [3]Kansal R et al. Sustained B cell depletion by CD19-targeted CAR T cells is a highly effective treatment for murine lupus. Sci Transl Med. 2019; 11:eaav1648. [4]Jin X et al. Therapeutic efficacy of anti-CD19 CAR-T cells in a mouse model of systemic lupus erythematosus. Cell Mol Immunol. 2021;18:1896-1903. [5]Christoph T et al. Reengineering chimeric antigen receptor T cells for targeted therapy of autoimmune disease. Science. 2016; 353:179-84. Acknowledgements I have acknowledgement Instituto de Salud Carlos III for their kind financial support (grant PI18/01917) Disclosure of Interests None declared.